The Program proposed will continue to have four major research divisions. The first will be concerned with an analysis of tissue damaging processes, by morphologic and morphometric techniques in cardiovascular, pulmonary, and renal disease. The objective is to correlate such measurements with clinical, functional, chemical and radiological parameters. Myocardial infarction, myocardial hypertrophy, isoproterenol induced myocardial injury, vascular prosthesis, and renal glomerular and interstitial disease will be examined. The second will be concerned with renal disease and transplantation emphasizing a) the classification of allograft rejection and c) correlation of rejection patterns in human renal allograft biopsies with in vitro immune surveillance studies. The third will concentrate on the examination, by ultrastructural and chemical techniques, the pathogenesis of chemically induced injury in the microcirculation and in a model of chronic duodenal ulcer. The fourth will investigate the biology of lymphocytes by a) studying the growth stimulating activity of serum albumin on Con A activated lymphocytes; b) isolation, purification, and characterization of lymphokines and c) determination of the mode of action of immunosuppressive drugs.